4 * We call the USB code inside a Linux-based peripheral device a "gadget"
5 * driver, except for the hardware-specific bus glue. One USB host can
6 * master many USB gadgets, but the gadgets are only slaved to one host.
9 * (C) Copyright 2002-2004 by David Brownell
10 * All Rights Reserved.
12 * This software is licensed under the GNU GPL version 2.
15 #ifndef __LINUX_USB_GADGET_H
16 #define __LINUX_USB_GADGET_H
18 #include <linux/device.h>
19 #include <linux/errno.h>
20 #include <linux/init.h>
21 #include <linux/list.h>
22 #include <linux/slab.h>
23 #include <linux/types.h>
24 #include <linux/usb/ch9.h>
29 * struct usb_request - describes one i/o request
30 * @buf: Buffer used for data. Always provide this; some controllers
31 * only use PIO, or don't use DMA for some endpoints.
32 * @dma: DMA address corresponding to 'buf'. If you don't set this
33 * field, and the usb controller needs one, it is responsible
34 * for mapping and unmapping the buffer.
35 * @length: Length of that data
36 * @stream_id: The stream id, when USB3.0 bulk streams are being used
37 * @no_interrupt: If true, hints that no completion irq is needed.
38 * Helpful sometimes with deep request queues that are handled
39 * directly by DMA controllers.
40 * @zero: If true, when writing data, makes the last packet be "short"
41 * by adding a zero length packet as needed;
42 * @short_not_ok: When reading data, makes short packets be
43 * treated as errors (queue stops advancing till cleanup).
44 * @complete: Function called when request completes, so this request and
45 * its buffer may be re-used. The function will always be called with
46 * interrupts disabled, and it must not sleep.
47 * Reads terminate with a short packet, or when the buffer fills,
48 * whichever comes first. When writes terminate, some data bytes
49 * will usually still be in flight (often in a hardware fifo).
50 * Errors (for reads or writes) stop the queue from advancing
51 * until the completion function returns, so that any transfers
52 * invalidated by the error may first be dequeued.
53 * @context: For use by the completion callback
54 * @list: For use by the gadget driver.
55 * @status: Reports completion code, zero or a negative errno.
56 * Normally, faults block the transfer queue from advancing until
57 * the completion callback returns.
58 * Code "-ESHUTDOWN" indicates completion caused by device disconnect,
59 * or when the driver disabled the endpoint.
60 * @actual: Reports bytes transferred to/from the buffer. For reads (OUT
61 * transfers) this may be less than the requested length. If the
62 * short_not_ok flag is set, short reads are treated as errors
63 * even when status otherwise indicates successful completion.
64 * Note that for writes (IN transfers) some data bytes may still
65 * reside in a device-side FIFO when the request is reported as
68 * These are allocated/freed through the endpoint they're used with. The
69 * hardware's driver can add extra per-request data to the memory it returns,
70 * which often avoids separate memory allocations (potential failures),
71 * later when the request is queued.
73 * Request flags affect request handling, such as whether a zero length
74 * packet is written (the "zero" flag), whether a short read should be
75 * treated as an error (blocking request queue advance, the "short_not_ok"
76 * flag), or hinting that an interrupt is not required (the "no_interrupt"
77 * flag, for use with deep request queues).
79 * Bulk endpoints can use any size buffers, and can also be used for interrupt
80 * transfers. interrupt-only endpoints can be much less functional.
82 * NOTE: this is analogous to 'struct urb' on the host side, except that
83 * it's thinner and promotes more pre-allocation.
91 unsigned stream_id
:16;
92 unsigned no_interrupt
:1;
94 unsigned short_not_ok
:1;
96 void (*complete
)(struct usb_ep
*ep
,
97 struct usb_request
*req
);
99 struct list_head list
;
105 /*-------------------------------------------------------------------------*/
107 /* endpoint-specific parts of the api to the usb controller hardware.
108 * unlike the urb model, (de)multiplexing layers are not required.
109 * (so this api could slash overhead if used on the host side...)
111 * note that device side usb controllers commonly differ in how many
112 * endpoints they support, as well as their capabilities.
115 int (*enable
) (struct usb_ep
*ep
,
116 const struct usb_endpoint_descriptor
*desc
);
117 int (*disable
) (struct usb_ep
*ep
);
119 struct usb_request
*(*alloc_request
) (struct usb_ep
*ep
,
121 void (*free_request
) (struct usb_ep
*ep
, struct usb_request
*req
);
123 int (*queue
) (struct usb_ep
*ep
, struct usb_request
*req
,
125 int (*dequeue
) (struct usb_ep
*ep
, struct usb_request
*req
);
127 int (*set_halt
) (struct usb_ep
*ep
, int value
);
128 int (*set_wedge
) (struct usb_ep
*ep
);
130 int (*fifo_status
) (struct usb_ep
*ep
);
131 void (*fifo_flush
) (struct usb_ep
*ep
);
135 * struct usb_ep - device side representation of USB endpoint
136 * @name:identifier for the endpoint, such as "ep-a" or "ep9in-bulk"
137 * @ops: Function pointers used to access hardware-specific operations.
138 * @ep_list:the gadget's ep_list holds all of its endpoints
139 * @maxpacket:The maximum packet size used on this endpoint. The initial
140 * value can sometimes be reduced (hardware allowing), according to
141 * the endpoint descriptor used to configure the endpoint.
142 * @max_streams: The maximum number of streams supported
143 * by this EP (0 - 16, actual number is 2^n)
144 * @mult: multiplier, 'mult' value for SS Isoc EPs
145 * @maxburst: the maximum number of bursts supported by this EP (for usb3)
146 * @driver_data:for use by the gadget driver.
147 * @address: used to identify the endpoint when finding descriptor that
148 * matches connection speed
149 * @desc: endpoint descriptor. This pointer is set before the endpoint is
150 * enabled and remains valid until the endpoint is disabled.
151 * @comp_desc: In case of SuperSpeed support, this is the endpoint companion
152 * descriptor that is used to configure the endpoint
154 * the bus controller driver lists all the general purpose endpoints in
155 * gadget->ep_list. the control endpoint (gadget->ep0) is not in that list,
156 * and is accessed only in response to a driver setup() callback.
162 const struct usb_ep_ops
*ops
;
163 struct list_head ep_list
;
164 unsigned maxpacket
:16;
165 unsigned max_streams
:16;
169 const struct usb_endpoint_descriptor
*desc
;
170 const struct usb_ss_ep_comp_descriptor
*comp_desc
;
173 /*-------------------------------------------------------------------------*/
176 * usb_ep_enable - configure endpoint, making it usable
177 * @ep:the endpoint being configured. may not be the endpoint named "ep0".
178 * drivers discover endpoints through the ep_list of a usb_gadget.
180 * When configurations are set, or when interface settings change, the driver
181 * will enable or disable the relevant endpoints. while it is enabled, an
182 * endpoint may be used for i/o until the driver receives a disconnect() from
183 * the host or until the endpoint is disabled.
185 * the ep0 implementation (which calls this routine) must ensure that the
186 * hardware capabilities of each endpoint match the descriptor provided
187 * for it. for example, an endpoint named "ep2in-bulk" would be usable
188 * for interrupt transfers as well as bulk, but it likely couldn't be used
189 * for iso transfers or for endpoint 14. some endpoints are fully
190 * configurable, with more generic names like "ep-a". (remember that for
191 * USB, "in" means "towards the USB master".)
193 * returns zero, or a negative error code.
195 static inline int usb_ep_enable(struct usb_ep
*ep
)
197 return ep
->ops
->enable(ep
, ep
->desc
);
201 * usb_ep_disable - endpoint is no longer usable
202 * @ep:the endpoint being unconfigured. may not be the endpoint named "ep0".
204 * no other task may be using this endpoint when this is called.
205 * any pending and uncompleted requests will complete with status
206 * indicating disconnect (-ESHUTDOWN) before this call returns.
207 * gadget drivers must call usb_ep_enable() again before queueing
208 * requests to the endpoint.
210 * returns zero, or a negative error code.
212 static inline int usb_ep_disable(struct usb_ep
*ep
)
214 return ep
->ops
->disable(ep
);
218 * usb_ep_alloc_request - allocate a request object to use with this endpoint
219 * @ep:the endpoint to be used with with the request
220 * @gfp_flags:GFP_* flags to use
222 * Request objects must be allocated with this call, since they normally
223 * need controller-specific setup and may even need endpoint-specific
224 * resources such as allocation of DMA descriptors.
225 * Requests may be submitted with usb_ep_queue(), and receive a single
226 * completion callback. Free requests with usb_ep_free_request(), when
227 * they are no longer needed.
229 * Returns the request, or null if one could not be allocated.
231 static inline struct usb_request
*usb_ep_alloc_request(struct usb_ep
*ep
,
234 return ep
->ops
->alloc_request(ep
, gfp_flags
);
238 * usb_ep_free_request - frees a request object
239 * @ep:the endpoint associated with the request
240 * @req:the request being freed
242 * Reverses the effect of usb_ep_alloc_request().
243 * Caller guarantees the request is not queued, and that it will
244 * no longer be requeued (or otherwise used).
246 static inline void usb_ep_free_request(struct usb_ep
*ep
,
247 struct usb_request
*req
)
249 ep
->ops
->free_request(ep
, req
);
253 * usb_ep_queue - queues (submits) an I/O request to an endpoint.
254 * @ep:the endpoint associated with the request
255 * @req:the request being submitted
256 * @gfp_flags: GFP_* flags to use in case the lower level driver couldn't
257 * pre-allocate all necessary memory with the request.
259 * This tells the device controller to perform the specified request through
260 * that endpoint (reading or writing a buffer). When the request completes,
261 * including being canceled by usb_ep_dequeue(), the request's completion
262 * routine is called to return the request to the driver. Any endpoint
263 * (except control endpoints like ep0) may have more than one transfer
264 * request queued; they complete in FIFO order. Once a gadget driver
265 * submits a request, that request may not be examined or modified until it
266 * is given back to that driver through the completion callback.
268 * Each request is turned into one or more packets. The controller driver
269 * never merges adjacent requests into the same packet. OUT transfers
270 * will sometimes use data that's already buffered in the hardware.
271 * Drivers can rely on the fact that the first byte of the request's buffer
272 * always corresponds to the first byte of some USB packet, for both
273 * IN and OUT transfers.
275 * Bulk endpoints can queue any amount of data; the transfer is packetized
276 * automatically. The last packet will be short if the request doesn't fill it
277 * out completely. Zero length packets (ZLPs) should be avoided in portable
278 * protocols since not all usb hardware can successfully handle zero length
279 * packets. (ZLPs may be explicitly written, and may be implicitly written if
280 * the request 'zero' flag is set.) Bulk endpoints may also be used
281 * for interrupt transfers; but the reverse is not true, and some endpoints
282 * won't support every interrupt transfer. (Such as 768 byte packets.)
284 * Interrupt-only endpoints are less functional than bulk endpoints, for
285 * example by not supporting queueing or not handling buffers that are
286 * larger than the endpoint's maxpacket size. They may also treat data
287 * toggle differently.
289 * Control endpoints ... after getting a setup() callback, the driver queues
290 * one response (even if it would be zero length). That enables the
291 * status ack, after transferring data as specified in the response. Setup
292 * functions may return negative error codes to generate protocol stalls.
293 * (Note that some USB device controllers disallow protocol stall responses
294 * in some cases.) When control responses are deferred (the response is
295 * written after the setup callback returns), then usb_ep_set_halt() may be
296 * used on ep0 to trigger protocol stalls. Depending on the controller,
297 * it may not be possible to trigger a status-stage protocol stall when the
298 * data stage is over, that is, from within the response's completion
301 * For periodic endpoints, like interrupt or isochronous ones, the usb host
302 * arranges to poll once per interval, and the gadget driver usually will
303 * have queued some data to transfer at that time.
305 * Returns zero, or a negative error code. Endpoints that are not enabled
306 * report errors; errors will also be
307 * reported when the usb peripheral is disconnected.
309 static inline int usb_ep_queue(struct usb_ep
*ep
,
310 struct usb_request
*req
, gfp_t gfp_flags
)
312 return ep
->ops
->queue(ep
, req
, gfp_flags
);
316 * usb_ep_dequeue - dequeues (cancels, unlinks) an I/O request from an endpoint
317 * @ep:the endpoint associated with the request
318 * @req:the request being canceled
320 * if the request is still active on the endpoint, it is dequeued and its
321 * completion routine is called (with status -ECONNRESET); else a negative
322 * error code is returned.
324 * note that some hardware can't clear out write fifos (to unlink the request
325 * at the head of the queue) except as part of disconnecting from usb. such
326 * restrictions prevent drivers from supporting configuration changes,
327 * even to configuration zero (a "chapter 9" requirement).
329 static inline int usb_ep_dequeue(struct usb_ep
*ep
, struct usb_request
*req
)
331 return ep
->ops
->dequeue(ep
, req
);
335 * usb_ep_set_halt - sets the endpoint halt feature.
336 * @ep: the non-isochronous endpoint being stalled
338 * Use this to stall an endpoint, perhaps as an error report.
339 * Except for control endpoints,
340 * the endpoint stays halted (will not stream any data) until the host
341 * clears this feature; drivers may need to empty the endpoint's request
342 * queue first, to make sure no inappropriate transfers happen.
344 * Note that while an endpoint CLEAR_FEATURE will be invisible to the
345 * gadget driver, a SET_INTERFACE will not be. To reset endpoints for the
346 * current altsetting, see usb_ep_clear_halt(). When switching altsettings,
347 * it's simplest to use usb_ep_enable() or usb_ep_disable() for the endpoints.
349 * Returns zero, or a negative error code. On success, this call sets
350 * underlying hardware state that blocks data transfers.
351 * Attempts to halt IN endpoints will fail (returning -EAGAIN) if any
352 * transfer requests are still queued, or if the controller hardware
353 * (usually a FIFO) still holds bytes that the host hasn't collected.
355 static inline int usb_ep_set_halt(struct usb_ep
*ep
)
357 return ep
->ops
->set_halt(ep
, 1);
361 * usb_ep_clear_halt - clears endpoint halt, and resets toggle
362 * @ep:the bulk or interrupt endpoint being reset
364 * Use this when responding to the standard usb "set interface" request,
365 * for endpoints that aren't reconfigured, after clearing any other state
366 * in the endpoint's i/o queue.
368 * Returns zero, or a negative error code. On success, this call clears
369 * the underlying hardware state reflecting endpoint halt and data toggle.
370 * Note that some hardware can't support this request (like pxa2xx_udc),
371 * and accordingly can't correctly implement interface altsettings.
373 static inline int usb_ep_clear_halt(struct usb_ep
*ep
)
375 return ep
->ops
->set_halt(ep
, 0);
379 * usb_ep_set_wedge - sets the halt feature and ignores clear requests
380 * @ep: the endpoint being wedged
382 * Use this to stall an endpoint and ignore CLEAR_FEATURE(HALT_ENDPOINT)
383 * requests. If the gadget driver clears the halt status, it will
384 * automatically unwedge the endpoint.
386 * Returns zero on success, else negative errno.
389 usb_ep_set_wedge(struct usb_ep
*ep
)
391 if (ep
->ops
->set_wedge
)
392 return ep
->ops
->set_wedge(ep
);
394 return ep
->ops
->set_halt(ep
, 1);
398 * usb_ep_fifo_status - returns number of bytes in fifo, or error
399 * @ep: the endpoint whose fifo status is being checked.
401 * FIFO endpoints may have "unclaimed data" in them in certain cases,
402 * such as after aborted transfers. Hosts may not have collected all
403 * the IN data written by the gadget driver (and reported by a request
404 * completion). The gadget driver may not have collected all the data
405 * written OUT to it by the host. Drivers that need precise handling for
406 * fault reporting or recovery may need to use this call.
408 * This returns the number of such bytes in the fifo, or a negative
409 * errno if the endpoint doesn't use a FIFO or doesn't support such
412 static inline int usb_ep_fifo_status(struct usb_ep
*ep
)
414 if (ep
->ops
->fifo_status
)
415 return ep
->ops
->fifo_status(ep
);
421 * usb_ep_fifo_flush - flushes contents of a fifo
422 * @ep: the endpoint whose fifo is being flushed.
424 * This call may be used to flush the "unclaimed data" that may exist in
425 * an endpoint fifo after abnormal transaction terminations. The call
426 * must never be used except when endpoint is not being used for any
427 * protocol translation.
429 static inline void usb_ep_fifo_flush(struct usb_ep
*ep
)
431 if (ep
->ops
->fifo_flush
)
432 ep
->ops
->fifo_flush(ep
);
436 /*-------------------------------------------------------------------------*/
438 struct usb_dcd_config_params
{
439 __u8 bU1devExitLat
; /* U1 Device exit Latency */
440 #define USB_DEFULT_U1_DEV_EXIT_LAT 0x01 /* Less then 1 microsec */
441 __le16 bU2DevExitLat
; /* U2 Device exit Latency */
442 #define USB_DEFULT_U2_DEV_EXIT_LAT 0x1F4 /* Less then 500 microsec */
447 struct usb_gadget_driver
;
449 /* the rest of the api to the controller hardware: device operations,
450 * which don't involve endpoints (or i/o).
452 struct usb_gadget_ops
{
453 int (*get_frame
)(struct usb_gadget
*);
454 int (*wakeup
)(struct usb_gadget
*);
455 int (*set_selfpowered
) (struct usb_gadget
*, int is_selfpowered
);
456 int (*vbus_session
) (struct usb_gadget
*, int is_active
);
457 int (*vbus_draw
) (struct usb_gadget
*, unsigned mA
);
458 int (*pullup
) (struct usb_gadget
*, int is_on
);
459 int (*ioctl
)(struct usb_gadget
*,
460 unsigned code
, unsigned long param
);
461 void (*get_config_params
)(struct usb_dcd_config_params
*);
462 int (*start
)(struct usb_gadget_driver
*,
463 int (*bind
)(struct usb_gadget
*));
464 int (*stop
)(struct usb_gadget_driver
*);
468 * struct usb_gadget - represents a usb slave device
469 * @ops: Function pointers used to access hardware-specific operations.
470 * @ep0: Endpoint zero, used when reading or writing responses to
471 * driver setup() requests
472 * @ep_list: List of other endpoints supported by the device.
473 * @speed: Speed of current connection to USB host.
474 * @is_dualspeed: True if the controller supports both high and full speed
475 * operation. If it does, the gadget driver must also support both.
476 * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
477 * gadget driver must provide a USB OTG descriptor.
478 * @is_a_peripheral: False unless is_otg, the "A" end of a USB cable
479 * is in the Mini-AB jack, and HNP has been used to switch roles
480 * so that the "A" device currently acts as A-Peripheral, not A-Host.
481 * @a_hnp_support: OTG device feature flag, indicating that the A-Host
482 * supports HNP at this port.
483 * @a_alt_hnp_support: OTG device feature flag, indicating that the A-Host
484 * only supports HNP on a different root port.
485 * @b_hnp_enable: OTG device feature flag, indicating that the A-Host
486 * enabled HNP support.
487 * @name: Identifies the controller hardware type. Used in diagnostics
488 * and sometimes configuration.
489 * @dev: Driver model state for this abstract device.
491 * Gadgets have a mostly-portable "gadget driver" implementing device
492 * functions, handling all usb configurations and interfaces. Gadget
493 * drivers talk to hardware-specific code indirectly, through ops vectors.
494 * That insulates the gadget driver from hardware details, and packages
495 * the hardware endpoints through generic i/o queues. The "usb_gadget"
496 * and "usb_ep" interfaces provide that insulation from the hardware.
498 * Except for the driver data, all fields in this structure are
499 * read-only to the gadget driver. That driver data is part of the
500 * "driver model" infrastructure in 2.6 (and later) kernels, and for
501 * earlier systems is grouped in a similar structure that's not known
502 * to the rest of the kernel.
504 * Values of the three OTG device feature flags are updated before the
505 * setup() call corresponding to USB_REQ_SET_CONFIGURATION, and before
506 * driver suspend() calls. They are valid only when is_otg, and when the
507 * device is acting as a B-Peripheral (so is_a_peripheral is false).
510 /* readonly to gadget driver */
511 const struct usb_gadget_ops
*ops
;
513 struct list_head ep_list
; /* of usb_ep */
514 enum usb_device_speed speed
;
515 unsigned is_dualspeed
:1;
517 unsigned is_a_peripheral
:1;
518 unsigned b_hnp_enable
:1;
519 unsigned a_hnp_support
:1;
520 unsigned a_alt_hnp_support
:1;
525 static inline void set_gadget_data(struct usb_gadget
*gadget
, void *data
)
526 { dev_set_drvdata(&gadget
->dev
, data
); }
527 static inline void *get_gadget_data(struct usb_gadget
*gadget
)
528 { return dev_get_drvdata(&gadget
->dev
); }
529 static inline struct usb_gadget
*dev_to_usb_gadget(struct device
*dev
)
531 return container_of(dev
, struct usb_gadget
, dev
);
534 /* iterates the non-control endpoints; 'tmp' is a struct usb_ep pointer */
535 #define gadget_for_each_ep(tmp, gadget) \
536 list_for_each_entry(tmp, &(gadget)->ep_list, ep_list)
540 * gadget_is_dualspeed - return true iff the hardware handles high speed
541 * @g: controller that might support both high and full speeds
543 static inline int gadget_is_dualspeed(struct usb_gadget
*g
)
545 #ifdef CONFIG_USB_GADGET_DUALSPEED
546 /* runtime test would check "g->is_dualspeed" ... that might be
547 * useful to work around hardware bugs, but is mostly pointless
556 * gadget_is_superspeed() - return true if the hardware handles
558 * @g: controller that might support supper speed
560 static inline int gadget_is_superspeed(struct usb_gadget
*g
)
562 #ifdef CONFIG_USB_GADGET_SUPERSPEED
564 * runtime test would check "g->is_superspeed" ... that might be
565 * useful to work around hardware bugs, but is mostly pointless
574 * gadget_is_otg - return true iff the hardware is OTG-ready
575 * @g: controller that might have a Mini-AB connector
577 * This is a runtime test, since kernels with a USB-OTG stack sometimes
578 * run on boards which only have a Mini-B (or Mini-A) connector.
580 static inline int gadget_is_otg(struct usb_gadget
*g
)
582 #ifdef CONFIG_USB_OTG
590 * usb_gadget_frame_number - returns the current frame number
591 * @gadget: controller that reports the frame number
593 * Returns the usb frame number, normally eleven bits from a SOF packet,
594 * or negative errno if this device doesn't support this capability.
596 static inline int usb_gadget_frame_number(struct usb_gadget
*gadget
)
598 return gadget
->ops
->get_frame(gadget
);
602 * usb_gadget_wakeup - tries to wake up the host connected to this gadget
603 * @gadget: controller used to wake up the host
605 * Returns zero on success, else negative error code if the hardware
606 * doesn't support such attempts, or its support has not been enabled
607 * by the usb host. Drivers must return device descriptors that report
608 * their ability to support this, or hosts won't enable it.
610 * This may also try to use SRP to wake the host and start enumeration,
611 * even if OTG isn't otherwise in use. OTG devices may also start
612 * remote wakeup even when hosts don't explicitly enable it.
614 static inline int usb_gadget_wakeup(struct usb_gadget
*gadget
)
616 if (!gadget
->ops
->wakeup
)
618 return gadget
->ops
->wakeup(gadget
);
622 * usb_gadget_set_selfpowered - sets the device selfpowered feature.
623 * @gadget:the device being declared as self-powered
625 * this affects the device status reported by the hardware driver
626 * to reflect that it now has a local power supply.
628 * returns zero on success, else negative errno.
630 static inline int usb_gadget_set_selfpowered(struct usb_gadget
*gadget
)
632 if (!gadget
->ops
->set_selfpowered
)
634 return gadget
->ops
->set_selfpowered(gadget
, 1);
638 * usb_gadget_clear_selfpowered - clear the device selfpowered feature.
639 * @gadget:the device being declared as bus-powered
641 * this affects the device status reported by the hardware driver.
642 * some hardware may not support bus-powered operation, in which
643 * case this feature's value can never change.
645 * returns zero on success, else negative errno.
647 static inline int usb_gadget_clear_selfpowered(struct usb_gadget
*gadget
)
649 if (!gadget
->ops
->set_selfpowered
)
651 return gadget
->ops
->set_selfpowered(gadget
, 0);
655 * usb_gadget_vbus_connect - Notify controller that VBUS is powered
656 * @gadget:The device which now has VBUS power.
659 * This call is used by a driver for an external transceiver (or GPIO)
660 * that detects a VBUS power session starting. Common responses include
661 * resuming the controller, activating the D+ (or D-) pullup to let the
662 * host detect that a USB device is attached, and starting to draw power
663 * (8mA or possibly more, especially after SET_CONFIGURATION).
665 * Returns zero on success, else negative errno.
667 static inline int usb_gadget_vbus_connect(struct usb_gadget
*gadget
)
669 if (!gadget
->ops
->vbus_session
)
671 return gadget
->ops
->vbus_session(gadget
, 1);
675 * usb_gadget_vbus_draw - constrain controller's VBUS power usage
676 * @gadget:The device whose VBUS usage is being described
677 * @mA:How much current to draw, in milliAmperes. This should be twice
678 * the value listed in the configuration descriptor bMaxPower field.
680 * This call is used by gadget drivers during SET_CONFIGURATION calls,
681 * reporting how much power the device may consume. For example, this
682 * could affect how quickly batteries are recharged.
684 * Returns zero on success, else negative errno.
686 static inline int usb_gadget_vbus_draw(struct usb_gadget
*gadget
, unsigned mA
)
688 if (!gadget
->ops
->vbus_draw
)
690 return gadget
->ops
->vbus_draw(gadget
, mA
);
694 * usb_gadget_vbus_disconnect - notify controller about VBUS session end
695 * @gadget:the device whose VBUS supply is being described
698 * This call is used by a driver for an external transceiver (or GPIO)
699 * that detects a VBUS power session ending. Common responses include
700 * reversing everything done in usb_gadget_vbus_connect().
702 * Returns zero on success, else negative errno.
704 static inline int usb_gadget_vbus_disconnect(struct usb_gadget
*gadget
)
706 if (!gadget
->ops
->vbus_session
)
708 return gadget
->ops
->vbus_session(gadget
, 0);
712 * usb_gadget_connect - software-controlled connect to USB host
713 * @gadget:the peripheral being connected
715 * Enables the D+ (or potentially D-) pullup. The host will start
716 * enumerating this gadget when the pullup is active and a VBUS session
717 * is active (the link is powered). This pullup is always enabled unless
718 * usb_gadget_disconnect() has been used to disable it.
720 * Returns zero on success, else negative errno.
722 static inline int usb_gadget_connect(struct usb_gadget
*gadget
)
724 if (!gadget
->ops
->pullup
)
726 return gadget
->ops
->pullup(gadget
, 1);
730 * usb_gadget_disconnect - software-controlled disconnect from USB host
731 * @gadget:the peripheral being disconnected
733 * Disables the D+ (or potentially D-) pullup, which the host may see
734 * as a disconnect (when a VBUS session is active). Not all systems
735 * support software pullup controls.
737 * This routine may be used during the gadget driver bind() call to prevent
738 * the peripheral from ever being visible to the USB host, unless later
739 * usb_gadget_connect() is called. For example, user mode components may
740 * need to be activated before the system can talk to hosts.
742 * Returns zero on success, else negative errno.
744 static inline int usb_gadget_disconnect(struct usb_gadget
*gadget
)
746 if (!gadget
->ops
->pullup
)
748 return gadget
->ops
->pullup(gadget
, 0);
752 /*-------------------------------------------------------------------------*/
755 * struct usb_gadget_driver - driver for usb 'slave' devices
756 * @function: String describing the gadget's function
757 * @speed: Highest speed the driver handles.
758 * @setup: Invoked for ep0 control requests that aren't handled by
759 * the hardware level driver. Most calls must be handled by
760 * the gadget driver, including descriptor and configuration
761 * management. The 16 bit members of the setup data are in
762 * USB byte order. Called in_interrupt; this may not sleep. Driver
763 * queues a response to ep0, or returns negative to stall.
764 * @disconnect: Invoked after all transfers have been stopped,
765 * when the host is disconnected. May be called in_interrupt; this
766 * may not sleep. Some devices can't detect disconnect, so this might
767 * not be called except as part of controller shutdown.
768 * @unbind: Invoked when the driver is unbound from a gadget,
769 * usually from rmmod (after a disconnect is reported).
770 * Called in a context that permits sleeping.
771 * @suspend: Invoked on USB suspend. May be called in_interrupt.
772 * @resume: Invoked on USB resume. May be called in_interrupt.
773 * @driver: Driver model state for this driver.
775 * Devices are disabled till a gadget driver successfully bind()s, which
776 * means the driver will handle setup() requests needed to enumerate (and
777 * meet "chapter 9" requirements) then do some useful work.
779 * If gadget->is_otg is true, the gadget driver must provide an OTG
780 * descriptor during enumeration, or else fail the bind() call. In such
781 * cases, no USB traffic may flow until both bind() returns without
782 * having called usb_gadget_disconnect(), and the USB host stack has
785 * Drivers use hardware-specific knowledge to configure the usb hardware.
786 * endpoint addressing is only one of several hardware characteristics that
787 * are in descriptors the ep0 implementation returns from setup() calls.
789 * Except for ep0 implementation, most driver code shouldn't need change to
790 * run on top of different usb controllers. It'll use endpoints set up by
791 * that ep0 implementation.
793 * The usb controller driver handles a few standard usb requests. Those
794 * include set_address, and feature flags for devices, interfaces, and
795 * endpoints (the get_status, set_feature, and clear_feature requests).
797 * Accordingly, the driver's setup() callback must always implement all
798 * get_descriptor requests, returning at least a device descriptor and
799 * a configuration descriptor. Drivers must make sure the endpoint
800 * descriptors match any hardware constraints. Some hardware also constrains
801 * other descriptors. (The pxa250 allows only configurations 1, 2, or 3).
803 * The driver's setup() callback must also implement set_configuration,
804 * and should also implement set_interface, get_configuration, and
805 * get_interface. Setting a configuration (or interface) is where
806 * endpoints should be activated or (config 0) shut down.
808 * (Note that only the default control endpoint is supported. Neither
809 * hosts nor devices generally support control traffic except to ep0.)
811 * Most devices will ignore USB suspend/resume operations, and so will
812 * not provide those callbacks. However, some may need to change modes
813 * when the host is not longer directing those activities. For example,
814 * local controls (buttons, dials, etc) may need to be re-enabled since
815 * the (remote) host can't do that any longer; or an error state might
816 * be cleared, to make the device behave identically whether or not
817 * power is maintained.
819 struct usb_gadget_driver
{
821 enum usb_device_speed speed
;
822 void (*unbind
)(struct usb_gadget
*);
823 int (*setup
)(struct usb_gadget
*,
824 const struct usb_ctrlrequest
*);
825 void (*disconnect
)(struct usb_gadget
*);
826 void (*suspend
)(struct usb_gadget
*);
827 void (*resume
)(struct usb_gadget
*);
829 /* FIXME support safe rmmod */
830 struct device_driver driver
;
835 /*-------------------------------------------------------------------------*/
837 /* driver modules register and unregister, as usual.
838 * these calls must be made in a context that can sleep.
840 * these will usually be implemented directly by the hardware-dependent
841 * usb bus interface driver, which will only support a single driver.
845 * usb_gadget_probe_driver - probe a gadget driver
846 * @driver: the driver being registered
847 * @bind: the driver's bind callback
850 * Call this in your gadget driver's module initialization function,
851 * to tell the underlying usb controller driver about your driver.
852 * The @bind() function will be called to bind it to a gadget before this
853 * registration call returns. It's expected that the @bind() function will
854 * be in init sections.
856 int usb_gadget_probe_driver(struct usb_gadget_driver
*driver
,
857 int (*bind
)(struct usb_gadget
*));
860 * usb_gadget_unregister_driver - unregister a gadget driver
861 * @driver:the driver being unregistered
864 * Call this in your gadget driver's module cleanup function,
865 * to tell the underlying usb controller that your driver is
866 * going away. If the controller is connected to a USB host,
867 * it will first disconnect(). The driver is also requested
868 * to unbind() and clean up any device state, before this procedure
869 * finally returns. It's expected that the unbind() functions
870 * will in in exit sections, so may not be linked in some kernels.
872 int usb_gadget_unregister_driver(struct usb_gadget_driver
*driver
);
874 extern int usb_add_gadget_udc(struct device
*parent
, struct usb_gadget
*gadget
);
875 extern void usb_del_gadget_udc(struct usb_gadget
*gadget
);
877 /*-------------------------------------------------------------------------*/
879 /* utility to simplify dealing with string descriptors */
882 * struct usb_string - wraps a C string and its USB id
883 * @id:the (nonzero) ID for this string
884 * @s:the string, in UTF-8 encoding
886 * If you're using usb_gadget_get_string(), use this to wrap a string
887 * together with its ID.
895 * struct usb_gadget_strings - a set of USB strings in a given language
896 * @language:identifies the strings' language (0x0409 for en-us)
897 * @strings:array of strings with their ids
899 * If you're using usb_gadget_get_string(), use this to wrap all the
900 * strings for a given language.
902 struct usb_gadget_strings
{
903 u16 language
; /* 0x0409 for en-us */
904 struct usb_string
*strings
;
907 /* put descriptor for string with that id into buf (buflen >= 256) */
908 int usb_gadget_get_string(struct usb_gadget_strings
*table
, int id
, u8
*buf
);
910 /*-------------------------------------------------------------------------*/
912 /* utility to simplify managing config descriptors */
914 /* write vector of descriptors into buffer */
915 int usb_descriptor_fillbuf(void *, unsigned,
916 const struct usb_descriptor_header
**);
918 /* build config descriptor from single descriptor vector */
919 int usb_gadget_config_buf(const struct usb_config_descriptor
*config
,
920 void *buf
, unsigned buflen
, const struct usb_descriptor_header
**desc
);
922 /* copy a NULL-terminated vector of descriptors */
923 struct usb_descriptor_header
**usb_copy_descriptors(
924 struct usb_descriptor_header
**);
927 * usb_free_descriptors - free descriptors returned by usb_copy_descriptors()
928 * @v: vector of descriptors
930 static inline void usb_free_descriptors(struct usb_descriptor_header
**v
)
935 /*-------------------------------------------------------------------------*/
937 /* utility wrapping a simple endpoint selection policy */
939 extern struct usb_ep
*usb_ep_autoconfig(struct usb_gadget
*,
940 struct usb_endpoint_descriptor
*);
943 extern struct usb_ep
*usb_ep_autoconfig_ss(struct usb_gadget
*,
944 struct usb_endpoint_descriptor
*,
945 struct usb_ss_ep_comp_descriptor
*);
947 extern void usb_ep_autoconfig_reset(struct usb_gadget
*);
949 #endif /* __LINUX_USB_GADGET_H */